In the letter, the senators are seeking details about Apple’s agreements with state and federal government for the development of the app and want to know if the program complies with the Health Insurance Portability and Accountability Act. The law, known as HIPAA, has strict guidelines for protecting patient privacy.

“In the interest of Americans during these unprecedented times, all data collected via Apple’s screening tools should remain confidential and must not be used for any commercial purposes in the future,” the letter said. “Additionally, we would like to better understand your efforts to keep any collected information safe from potential hackers, foreign state and non-state actors with nefarious intent, and other criminal enterprises.”

Apple partnered with the Centers for Disease Prevention and Control to develop the website and app. The two are seen as resources for people to stay informed on how to protect their health during the coronavirus outbreak.

Once users complete a list of questions, they will receive CDC recommendations for guidance on social distancing, self-isolation and whether a person should get tested for the virus.

Users are not required to sign-in or use an Apple ID.

Apple says it only collects information on user engagement so that the company can improve the site. “The information collected will not personally identify you,” Apple says on its website.